Racket including string engaging elastomeric bushings and pads

ABSTRACT

A STRUNG GAME RACKET IN WHICH THE PRIMARY STRINGS ARE BORNE ON THE SURFACES WHICH ARE RESILIENTLY-CUSHIONED BY ELASTOMERIC BUSHINGS AND PADS TO AMPLIFY STRING RECOVERY POWER UNDER HEAVY STRAIN AS WELL AS TO PREVENT STRING ABRASION AT POINTS OF CONCENTRATED SURFACE LOADING.

March 2, 1971 E. oLus 3,567,225

RACKET INCLUDING STRING ENGAGING ELAS'IOMERIC BUSHINGS AND PADS Filed March 26. 1968 -F I G. I

POLYURETHANE HARDNESS 95 SHORE A SCALE INVENTOR.

JAMES E. HOLLIS A5 ATTORNEYS United States Patent O 3,567,225 RACKET INCLUDING STRING ENGAGING ELASTOMERIC BUSHINGS AND PADS James E. Hollis, Providence, R.I., assignor to Brancroft Racket Company Filed Mar. 26, 1968, Ser. No. 716,208 Int. Cl. A63b 51/02 US. Cl. 273-73 3 Claims ABSTRACT OF THE DISCLOSURE A strung game racket in which the primary strings are borne on the surfaces which are resiliently-cushioned by elastomeric bushings and pads to amplify string recovery power under heavy strain as well as to prevent string abrasion at points of concentrated surface loading.

BACKGROUND OF THE INVENTION A game racket such as is used for the game of tennis comprises an oval frame with a handle extending along the major axis of the oval. A plurality of the center strings parallel to this axis carry from 70 to 75% of the playing load when the ball is properly struck. The strings are usually formed of animal gut which has some ealsticity so that they move the bores or openings on the frame through which they are strung as the ball is hit. Also there is some movement due to contraction and elongation from various amounts of dampness in the atmosphere. The strings make an obtuse angle at the point where they extend through the threading bores in the frame of the racket which is the point of Wear and usually breakage of a string occurs at this location. The maintenance of a balance so that the racket will have the proper feel to the user is of importance.

Attempts have been made to minimize wear at the location of the threading bores in the frame for the strings by the use of various means. Some of these means are extremely complicated and expensive to use while a major objection is that the racket is thrown out of balance by the use of such means. Inserts in the threading bores are of a material different, of course, than the material of the frame and have a different density and if of any material size will throw off the balance of the racket which is a major objection. Vibration is also a factor in being transmitted from the strung racket to the arm of the user and also the matter of control of the ball when stuck such as cutting the ball for backspin or the like is a consideration.

SUMMARY OF THE INVENTION The racket has its threading bored opening bushed With an elastomeric material of minimal size at the location where the strings have a bend and wear usually occurs and which serve as a cushioning means and prevents wear at these locations. Also cushioning is additionally provided by an elastomeric insert under the bight of the strings as they extend from one threading opening to another threading opening. The elastomeric material, such as polyurethane, which is of a different density than the material of the racket, is used in minimal amounts so that the balance of the racket will not be disturbed.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of the racket with the handle portion thereof broken away;

FIG. '2 is an edge elevation;

FIG. 3 is a top plan view of the upper edge of the racket with the center portion showing and broken away at the sides;

FIG. 4 is a sectional view on substantially line 44 of FIG. 3;

Patented Mar. 2, 1971 FIG. 5 is an edge view of a fragmental portion of the frame of the racket adjacent the throat portion of the frame; and

FIG. 6 is a sectional view of the throat portion.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the drawings, 10 designates the handle of a racket while 11 designates generally the frame comprising an oval portion 12 and throat portion 13 at the end of the handle 10. Openings or bores are provided through the frame generally parallel to the plane thereof for the reception of strings 14 which extend generally lengthwise of the major axis of the oval portion 12 parallel to this axis and also across the major axis or parallel to the minor axis of the oval so as to provide right angularly extending strings which are assembled in a generally one and one woven pattern.

The bores for the strings through the frame are symmetrically arranged and thus we see that there are bores 20, 21, 22 and so forth on one side of the center at the upper edge of the frame while there are bores 30, 31, 32 and so forth on the other side of the center of the frame at the upper edge thereof. At the lower or throat portion of the frame at the right side of the center, there are bores 40, 41, 42, 43, 44 and so forth while on the left side of the frame there are corresponding bores arranged as a mirror image of the openings in the series just mentioned and being substantially identical therewith.

A string is continuous in its extent but for the purpose of more accurate description is considered as a separate string in each of its spans between the bores or openings in the frame. Thus at the right side of the center in the drawing, a string extends through the opening 20, then through opening 40, and back through opening 41 where it now becomes string 51 to extend through opening 21, then back through bore 22 where it becomes string 52 and thence through bore 42 and back through bore 43 where it becomes string 53 and then back through an upper opening not here illustrated and so forth.

On the other side of the center of the racket, a string passes through opening 30 through lower openings and then becoming string 61 and then back through opening 31 and through opening 32 where it becomes string 62 and so forth similar to the strings 50, 51, 52, 53 as above described.

The string as it passes through one bore and then back through an adjacent bore a bight portion is formed as 71 etc. at the upper edge of the racket frame or a bight portion 80, 81, 82 etc. as it passes through bores of the lower or throat portion of the frame. At the junction of these bight portions with the strings extending therefrom, the string makes an angle as at 75, 76, 77, 85, 86, 87, 88, and as any movement of the string occurs as when a ball is struck, wear will be greater at the apex of this angle than at other locations. In fact, wherever there is an angle, this Will be a point of wear. Thus in addition to the points of wear adjacent each end of the bight above-referred to, there will also be a point of wear particularly in the lower or throat portion of the frame where the string 50, 51, 52 or 53 emerges from opening 40, 41, 42, or 43, such as at 95, 96, 97, 98 and so forth.

At these points if wear such as at 75, 76, 77, 85, 86, 87, 88 or 95, 96, 97, 98, I have inserted a polyurethane bushing by enlarging the bores at the very outer ends of the bores in a size to accommodate this larger diameter bushing. The bushing is of minimal axial extent and has an aperture therethrough for the reception of the string. The bushing is also of a size and shape to be flush with the outer surface of the frame or inner surface of the frame to which it is adjacent. Thus there are bushings 100 in the larger portion 25 of the bores 20, 101 in the larger portion 26 of the bore 21 and bushing 102 in the larger portion 27 of the bore 22, while there are bushings 110 in the larger portions 45 of the bore 40, 111 in the larger portion 46 of the bore 41 and so forth; While at the outer surface there is a bushing 120 in the larger portion 45' of the bore 40, larger bushing 121 in the larger portion 46' of the bore 41 and so forth.

Further in order to enhance the resilient action of the strings here provided, I have inserted pads 130 and 131 under the bight 80 and 81, and I provide these pads of a different resilience than the resilience of the bushings.

A polyurethane material is found to be good for the elastomeric action which I desire. Polyurethane material may have different degrees of hardness and I have found that for the bushing a hardness of 95 on the Shore A scale is desirable, while the hardness for the pad of the polyurethane material is preferably 85 on the Shore A scale. Thus there is a difference in the resilience of the materials used in the bushing and the pad.

I have found that a racket constructed as above provides a material dampening of the vibrations that the strings transmit to the handle and thus to the arm of the user. Further there is greater resilience in the strings of a racket constructed as above than where there is no elastomeric bushing or pad and this greater resilience, provides for a somewhat arcing of the strings to form a concave-like portion to extend the surface contact between the strings and a round tennis ball, and thus provide a better control of the ball when hit as it provides for a greater surface contact with the ball and thus when cutting the ball a better action is provided and one of greater control. Further by the use of minimal amounts of polyurethane, which is heavier than wood, and with a recessing of the wood, there is substantially no disturbance of balance in the racket which is exceedingly important to a fine player and yet with the minimal amount which is used an advantageous cushioning and dampening action on the strings is provided especially this being true in a racket which is formed of wood. Also the minimal amount of removal of the wood does not weaken the wooden racket to a detrimental extent. Further the movement of the string in the bore or opening through which it is threaded either by contraction or expansion of the gut due to dampness or by reason of the movement of the gut when the ball is struck is so cushioned by the elastomeric material that wear on the strings at the point of angle of the strings is minimized. I further believe that, by the use of this elastomeric material which has a rebound, the ball is more forcefully propelled than without it.

I claim:

1. A racket comprising an oval frame, throat area and handle, said frame provided with string receiving bores extending generally in the plane of said frame, said bores being formed with larger openings at the outer surface of said frame and at the inner surface of said frame in at least the area of said throat, said larger openings extending from the outer and inner surfaces of said frame inwardly a minor portion of the length of said bore, elastomeric bushings in said larger openings for direct contact with the racket strings, and elastomeric pads of lesser hardness than said elastomeric bushings formed on said outer surface between said larger openings in at least said throat area for resiliently supporting the racket strings.

2. A racket as in claim 1 wherein said elastomeric bushings are polyurethane of a hardness of substantially 95 on the Shore A scale.

3. A racket as in claim 1 wherein said elastomeric pads are polyurethane of a hardness of on the Shore A scale.

References Cited UNITED STATES PATENTS 1,523,865 1/1925 Craig 27373 1,585,416 5/1926 Rastetter 273-73 1,937,787 12/1933 Robinson 273-73 2,171,223 8/1939 Robinson 27373 2,542,661 2/1951 Godfrey 27373 2,742,289 4/1956 Allward 27373 3,452,990 7/1969 Nichols (27 3-Polyurethane Digest) FOREIGN PATENTS 1,059,989 11/1953 France 273-73 546,787 4/1956 Belgium 27373 8,206 1890 Great Britain 273-73 6,475 1906 Great Britain 27373 252,480 6/1926 Great Britain 27373 GEORGE J. MARLO, Primary 'Examiner R. I. APLEY, Assistant Examiner 

